diff --git a/language-agent/Tracing.proto b/language-agent/Tracing.proto
index 79af24f..2393bf8 100644
--- a/language-agent/Tracing.proto
+++ b/language-agent/Tracing.proto
@@ -72,6 +72,8 @@ message SegmentObject {
     // The agent/SDK could optimize or ignore some tracked spans for better performance.
     // In this case, the value should be flagged as TRUE.
     bool isSizeLimited = 6;
+    //add for internal use.
+    string namespace = 7;
 }
 
 // Segment reference represents the link between two existing segment.